Parental Underestimates of Child Weight: A Meta-analysis

Abstract

BACKGROUND AND OBJECTIVE: Parental perceptions of their children’s weight play an important role in obesity prevention and treatment. The objective of this study was to determine the proportion of parents worldwide who underestimate their children’s weight and moderators of such misperceptions.

METHODS: Original studies published to January 2013 were chosen through literature searches in PUBMED, PSYCHINFO, and CINAHL databases. References of retrieved articles were also searched for relevant studies. Studies were published in English and assessed parental perceptions of children’s weight and then compared perceptions to recognized standards for defining overweight based on anthropometric measures. Data were extracted on study-level constructs, child- and parent-characteristics, procedural characteristics, and parental underestimates separately for normal-weight and overweight/obese samples. Pooled effect sizes were calculated using random-effects models and adjusted for publication bias. Moderators were explored using mixed-effect models.

RESULTS: A total of 69 articles (representing 78 samples; n = 15 791) were included in the overweight/obese meta-analysis. Adjusted effect sizes revealed that 50.7% (95% confidence interval 31.1%–70.2%) of parents underestimate their overweight/obese children’s weight. Significant moderators of this effect included child’s age and BMI. A total of 52 articles (representing 59 samples; n = 64 895) were included in the normal-weight meta-analysis. Pooled effect sizes indicated that 14.3% (95% confidence interval 11.7%–17.4%) of parents underestimate their children’s normal-weight status. Significant moderators of this effect included child gender, parent weight, and the method (visual versus nonvisual) in which perception was assessed.

CONCLUSIONS: Half of parents underestimated their children’s overweight/obese status and a significant minority underestimated children’s normal weight. Pediatricians are well positioned to make efforts to remedy parental underestimates and promote adoption of healthy habits.

Approximately 31.7% of children aged 2 to 19 are overweight or obese in the United States, a prevalence rate that represents more than a threefold increase in childhood obesity over the past 30 years.1 Such a high rate warrants attention, given that obesity is associated with many adverse short- and long-term medical2–4 and psychosocial3,5 outcomes, and is a condition that most individuals do not outgrow. Overweight 2- to 5-year olds are 5 times more likely than their nonoverweight counterparts to be overweight at 12 years of age,6 and obesity in adolescence is highly predictive of adult adiposity.7

Given the far-reaching effects of childhood obesity, the issue should be addressed early and effectively. Requiring the active participation of parents is important, as they are influential in modeling and establishing children’s eating and physical activity patterns.8,9 Recommendations for the prevention of childhood obesity set forth by the American Academy of Pediatrics10 highlight the crucial role parents have in preventing childhood obesity, and evidence suggests that interventions involving parents tend to be the most successful.11,12 However, involvement requires that parents recognize and are concerned that their children are overweight.13–17 If parents are unable or unwilling to recognize that their children are overweight, or are simply not concerned about their child’s excess weight, they may lack the motivation to address the problem.17,18 Parents who believe their children are struggling with weight, however, may be more likely to model healthy behaviors and seek out resources to address their child’s weight.19,20 For example, research indicates that correct maternal perceptions of excess weight among young children resulted in greater weight loss over time compared with children whose weight was perceived incorrectly by their mothers.21

Nevertheless, parents are often oblivious to their children’s excess weight, with previous reviews on parental perceptions of children’s weight reporting that most parents fail to recognize their overweight children as such.19,20,22,23 Parental underestimates and lack of concern may not only prevent parents from performing actions to address their children’s weight, but may also influence overweight children to regard their weight status as normal and, thus, to further engage in obesogenic behaviors.24,25 Among normal-weight children, parental underestimates of their children’s weight may lead parents to encourage increased intake of food (ie, overintake) to facilitate growth/weight gain, thus placing their children at an increased risk of future overweight.26 Given that underestimates of both normal weight and overweight/obesity might exacerbate the development of excess weight, it is important to determine the prevalence of parental underestimates and what factors contribute to such views. Therefore, the current study’s purpose is to conduct a meta-analysis on parental underestimates of child weight. The overall proportion of parents who underestimate their child’s weight status will be estimated, and the moderating effects of study-level (eg, year of data collection), procedural (eg, method of assessment), and sample characteristics (eg, child and parent characteristics) will be examined.

Method

Study Selection

Research studies documenting parental perceptions of child weight were collected systematically via PUBMED, PSYCHINFO, and CINAHL (EBSCO) from September 2012 to January 2013. Search terms included the following: parental, maternal, mother, father, child, overweight, obesity, weight, and perceptions. These search terms were entered in various groupings to facilitate a comprehensive search. Also, references of relevant articles were hand-searched for additional studies and the “Related Articles” and “Cited by” functions in search engines were used.

Studies eligible for inclusion were those in which primary caregivers’ perceptions of their children’s weight (≥2 years of age) were assessed via Likert scale questions, classification into weight categories, pictorial methods, or reporting of height and weight, and were subsequently compared with recognized standards for defining overweight (eg, International Obesity Task Force) based on anthropometric measurements. If a study reported parental perceptions for >1 sample separately (eg, samples of 6- to 7- and 10- to 12-year-olds), these samples were treated independently. No restrictions were made based on geographic location, ethnicity, or publication date.

Exclusion criteria included nonpublished, non-English, and/or qualitative studies, as well as those that did not include objective anthropometric measurements of child weight/height to compare perceptions to or those that did not pair parent and child data. If studies reported >1 method of assessing parental perception (eg, choosing an image that best represented their child and verbally describing the child’s weight), only the visual method was included in analyses to minimize issues of dependency and increase power when comparing effect sizes obtained from the different assessment methods, given the small number of studies that used visual methods.27–31 For longitudinal studies, only the first assessment was used to ensure that all perceptions were counted only once in subsequent analyses. The guidelines set forth by the Preferred Reporting Items for Systematic Reviews and Meta-analyses were followed.32

Quality Assessment

Quality scoring of the studies collected was not conducted given that total quality scores are aggregates of quality components that may result in superfluous or even misleading relationships with the study outcomes (see Greenland33). Rather than constructing an aggregate quality score of various components that the coder must identify regardless, the effect of those components expected to reflect study quality (eg, assessment method, BMI cutoffs) were analyzed separately in mixed-effect models (see Tables 4 and 5).

Data Extraction

Data were extracted on study-level constructs, child and parent characteristics, procedural characteristics, and parental underestimates of child weight (see Tables 1, 2, and 3). Parental underestimates of child weight was the primary outcome. Among obese children, underestimation was defined as being classified as overweight, normal weight, or underweight. Among overweight children, underestimation was defined as being classified as normal weight or underweight. Parental underestimation of normal weight status (ie, being classified as underweight) was also examined and moderators for underestimates of normal weight were coded and examined separately (coded characteristics not shown; data can be requested from authors). For completeness, parental overestimation of normal weight status (ie, being classified as overweight/obese) was also examined, but proportions were negligible and beyond the current study’s focus on preventing childhood obesity (these data can also be requested from authors). Samples that were classified as “at-risk” for overweight were not examined given the inconsistent definition for at-risk across studies. When insufficient data were provided, authors were contacted and data from supplementary articles were extracted when possible.77 Two separate coders coded a proportion of studies (n = 22), and interrater reliability on outcomes and moderators was excellent (mean κ = 0.85, range = 0.67–1.00).101 Any inconsistencies were resolved through discussion until the coders reached consensus.

Statistical Procedures

Main effect and moderator analyses were performed in SPSS v.21.0 (IBM SPSS Statistics, IBM Corporation, Chicago, IL) using meta-analysis macros.102 For each study, 2 effect sizes were calculated, including the proportion of parents who (1) underestimated their child’s normal weight status; and (2) underestimated their child’s overweight/obese weight status. Each effect size was transformed into logits and the corresponding SEs were subsequently calculated.102After completion of analyses, effect sizes were transformed back into proportions to facilitate interpretation.

Pooled effect sizes were estimated via random effects models (using maximum likelihood), given the expected heterogeneity of the studies, and moderator analyses were performed by using mixed-effect models (with fixed and random effects). Hedges’103 analog to the analysis of variance approach for analyzing between-study variability in effect sizes was conducted to compare effect sizes by using categorical moderators (with a random effects variance component based on residual variance). Effect sizes were calculated for subsets of studies grouped according to the categorical moderator of interest, and heterogeneity of the effect sizes (as indicated by Q and I2 statistics102) both within and between categories was tested. Q and I2 statistics and P values were calculated and compared only when at least 2 of the subsets had 4 or more studies to avoid unstable results.104 To assess the relationship between effect sizes and continuous moderators, weighted least-squares regressions with random effects variance components based on residuals were used.102 SEs were adjusted for meta-analytic computations by dividing the SE of the regression coefficient by the square root of the mean-square residual and using the corrected SE in a z test to produce an accurate test of significance.

“Trim and fill” analyses were conducted to calculate the potential effect that publication bias might have.105 This procedure involves constructing a funnel plot in which the effect size of each study is plotted against precision (1/SE). If no publication bias exists, the plot is shaped like a funnel. However, given that studies with small samples and/or nonsignificant results are less likely to be published, there is a tendency for studies in the bottom left-hand corner of the plot to be missing.106 Using the logit effect sizes, the studies plotted farthest to the right of the graph (considered symmetrically unmatched) were trimmed. The missing counterparts (mirror images of the trimmed studies) were then imputed, allowing for computation of adjusted effect sizes and confidence intervals.

Summary of heterogeneity, point estimates, and uncertainty of effect sizes of parental underestimation of children’s normal weight status.

Using mixed-effects models, a number of moderator analyses were conducted to explain the heterogeneity in effect sizes (Tables 4 and 5). Factors extracted as potential moderators included the following: year of data collection, childhood obesity rate in country and state, child mean age, child gender, child BMI, child ethnicity, parent age, percentage of overweight parents in sample, assessment method (visual versus nonvisual) and BMI cutoffs. No study-level characteristics (eg, year of data collection) significantly moderated the rate of parental underestimation of child’s normal weight or overweight/obese status. Significant child characteristic moderators of parental underestimation of child’s overweight/obese weight status included age and BMI, such that underestimates were more likely among younger children and children with lower BMIs. Among normal-weight children, child gender significantly moderated parental underestimations, such that underestimates were more likely among samples with higher male proportions. No parental characteristics moderated the underestimation of overweight/obese child’s weight, although parental overweight percentage was a significant moderator of underestimation of their child’s normal weight, such that underestimates were more likely among normal-weight samples with higher proportions of overweight parents. For procedural characteristics, neither the type of BMI cutoff used nor the assessment method (visual versus nonvisual) were significant moderators of parental underestimation of child’s overweight/obese status. The use of visual assessment methods (eg, sketches or photographs) was a significant moderator of parental underestimation of child’s normal-weight status, although the Qw was significant (P < .001), indicating that visual assessment method did not account for the heterogeneity in effect sizes within the 8 studies that used a visual assessment method. Therefore, it is likely that some other factor is accounting for this difference.

The trim and fill method revealed asymmetry in the funnel plots for parental underestimation of their child’s overweight status. A total of 11 studies to the right of the mean were unmatched. The counterparts of these studies were imputed to the left of the mean, resulting in an adjusted main effect of 50.7% (95% CI 31.1%–70.2%). Data with regard to funnel plots and consequent adjustment of main effects are not shown. No asymmetry was indicated in the funnel plot of parental underestimation of their child’s normal weight.

Discussion

A large proportion of parents (50.7%, based on adjusted effect size) underestimated the weight of their overweight/obese children. These findings are generally consistent with a smaller systematic review22 that was published during the preparation of this article; however, our finding of 50.7% is likely lower because it was obtained through a more rigorous correction analysis. Results also indicate that 1 of 7 parents underestimated their child’s normal weight. Although much lower than the rate of underestimation among parents of overweight/obese children, this rate of underestimation among normal-weight children still warrants attention.

A variety of possible explanations for such high rates of parental underestimates of overweight/obese children’s weight have been posited. For instance, popular media reports regarding childhood obesity often stereotype overweight children by showing images of severely obese children, a practice that may distort parents’ understanding of what actually qualifies as overweight.24 It is also possible that parents are simply resistant to labeling or stigmatizing their children106 or, alternatively, may not be willing to recognize that their child is overweight because doing so would require that they recognize that they, too, may need to implement healthy lifestyle changes. Yet, underestimates may not be so intentional, as qualitative research indicates that parents simply do not consider their child to be overweight if he or she engages in physical activity, is not teased about his or her size, and has no obviously threatening health problems.107

Although the current meta-analysis was unable to test the previously discussed theories, potential moderators of underestimation were identified. First, parents were less likely to underestimate the weight of older overweight/obese children. Although parental perceptions become better over time, there is a rather high prevalence of overweight/obese 2- to 5-year-olds who are at risk for parental underestimation.1 Moreover, there is increasing evidence that excess weight in young children predicts excess weight in adolescence and adulthood.7 According to Jain et al,107 however, parents of young children believe their children will eventually “grow out” of the excess weight and that steady increases in height and weight indicate good parenting and nutrition. Although the high prevalence of overweight/obesity in young children indicates the importance of early intervention, these efforts are unlikely to be successful if parents are unaware or unconcerned about their children’s weight status. Whether parental misperceptions are equally related to a lower likelihood of parents intervening to make healthy lifestyle changes for both younger and older children, however, is not yet clear. This area, therefore, would be a valuable area for future investigation.

Parents were also less likely to underestimate the weight of overweight/obese children as BMI increased, indicating that children with a BMI-for-age percentile just over the cutoff for overweight were at greater risk for being misclassified by parents than those with a higher BMI and, thus, clearly overweight or obese. This suggests that parents are able to detect excess weight in extreme amounts, but tend not to be alarmed by small amounts of overweight. Children with greater fat mass (including those who just surpass BMI-for-age percentile cutoffs for overweight) tend to experience an increase in fat mass as they age, however.108 Thus, improving parents’ ability to recognize overweight, even in small magnitudes, may make it easier to intervene and reverse classification of overweight for those children who have just surpassed the cutoff.

Although not a significant moderator among overweight/obese children, child gender significantly moderated underestimation rates among normal-weight children. That is, underestimates were more likely as the proportion of boys in the sample increased, indicating that parents are more likely to underestimate the normal weight of their sons as compared with their daughters. Although this finding may reflect actual differences in body composition for male and female individuals,109 it is more probable that this tendency reflects what constitutes “ideal” body shapes for both boys and girls.110 In comparison with the “thin ideal” female body, a normal-weight daughter would likely be perceived as normal or even slightly overweight. However, in comparison with the expectation that boys should be big, strong, and muscular, normal-weight sons may be perceived as too small. Sons who are perceived as too small may not be provided with information regarding healthy eating and exercise.72 Rather, sons perceived as underweight may even be encouraged to overeat, as larger boys are considered to have a physical advantage over those who are smaller, placing these children at risk for future overweight.

A number of the variables explored revealed no moderating effects on the proportion of parents who underestimated child’s overweight/obese and normal-weight status. The nonsignificant findings regarding year of data collection and rate of childhood obesity in the country and/or state indicate that rates of inaccurate perceptions have tended to be fairly constant over the past 2 decades and in regions of high and low rates of obesity. Although the popular “what is common is normal” hypothesis95 is appealing (ie, in regions with high levels of obesity, overweight and obesity are considered normal), these data suggest that parents are simply inaccurate in their perceptions of children’s weight. Likewise, child gender, ethnicity, and parental overweight and age were not related to parental underestimates of overweight/obese status, suggesting that parental underestimation is a common phenomenon among parents of overweight/obese children, regardless of the child’s gender or ethnicity or the parent’s age or own weight status. Further indicative of the universal tendency to underestimate overweight/obese children’s weight, the proportion of parents who underestimated child’s overweight/obese status was also not significantly related to the type of assessment method or BMI cutoff used, indicating that regardless of how overweight/obesity is defined, the underestimation of overweight/obese children’s weight is prominent.

Clinical and Research Implications

The results of this meta-analysis highlight how important it is for pediatricians and health care providers to have discussions with all parents regarding their children’s weight. Even children who fall within the guidelines of “normal” weight may be at risk for overeating and, thus, overweight if their parents underestimate their weight. Given the numerous consequences of pediatric obesity and the importance of early identification, parental underestimates that might hinder timely recognition and intervention of clinical weight problems warrant attention. Specifically, methods to improve parental perceptions of children’s weight should be pursued, and pediatricians are in an ideal position to take steps to remedy such underestimates. Although the American Academy of Pediatrics recommends that pediatricians assess for overweight as a part of routine clinical practice,111 evidence suggests that the implementation of such recommendations is inadequate. For example, Barlow and colleagues10 found that only 41% of 557 children’s growth charts were up to date from a sample of diverse pediatrician practices, and only 6.1% of the children had their BMI charted. Improvement in pediatricians’ assessment of excess weight is necessary, therefore, as the absence of a pediatrician’s comment on their child’s weight status has been identified as one of the strongest predictors of parental misclassification of their child’s weight.28

Thus, it is recommended that pediatricians make it a priority to assess weight in all children who present to their practices, and communicate the results to parents in an easy-to-understand and sensitive manner. Prochaska and DiClemente’s112 stage of change theory offers a useful framework for communicating weight-related information to parents. Pediatricians should be familiar with how to approach families in precontemplation (ie, those not acknowledging the problem). The role of the pediatrician for such families will largely be that of awareness-raising, rather than pushing unsolicited advice regarding the implementation of lifestyle changes. Emerging evidence suggests that simply raising awareness may have beneficial effects: when parents are given a simple report outlining their child’s BMI, classification (ie, underweight, normal weight, overweight, or obese), and general guidelines regarding diet and physical activity, they become more accurate in assessing their child’s weight status.113 When parental perceptions regarding child weight are corrected, they are more likely to move from the precontemplation stage of change to the preparation or action stage of change.114 Thus, awareness-raising strategies may facilitate stage change which could further facilitate desired actions (eg, diet change, increased physical activity). Research on this topic indicates that accurate maternal perceptions of child weight do lead to changes in unhealthy behaviors, such as reductions in the hours children spend in sedentary activities.64 Further research should be conducted to evaluate what changes in both parent and child health behaviors and child weight status could be demonstrated with systematic physician behavior change and counseling. Such research would be especially informative for children ages 2 to 5 or for those who are at or just slightly above the 85th percentile, as these children are at higher risk for parental underestimation.

Strengths and Limitations

A number of limitations should be taken into consideration when interpreting the current findings. First, unpublished studies and those studies not published in English may have resulted in biased findings. Although publication bias analyses indicated that such a bias did not exist for the normal-weight sample, publication bias did exist for the overweight/obese sample. Thus, overweight/obese results should be interpreted with that limitation in mind, as the effect sizes of parental underestimates of their child’s weight in published literature may not be representative of all studies conducted on the topic. Likewise, relationships between moderators and parental underestimates may also not be truly representative of actual relationships between the constructs. This is an especially important consideration to keep in mind when interpreting null findings. Second, the impact of a number of moderators (eg, child and parent ethnicity, parental gender, parental education, socioeconomic status [SES]) could not be examined, given a lack of power, nor could multiple regression analyses be conducted, given the inconsistent reporting of similar variables across studies. Thus, the moderating effect of many potentially important variables not included in these analyses, as well as the unique contribution of those variables included, could not be determined. This is unfortunate given that (1) existing literature suggests important differences in parental perceptions of child weight based on factors such as parent gender, ethnicity, and SES,10,107,115 and (2) within-group heterogeneity remained in the perception assessment method analysis for the normal-weight sample and multiple regression analyses could not be conducted to examine what other factors may account for the remaining variance in effect sizes. There was also a striking inconsistency in the manner in which a number of moderators (eg, parental education, SES) were reported in the original studies, making it impossible to systematically code for and examine these moderators. Additionally, power was limited for a number of the moderator analyses (eg, child ethnicity, parent age), so results should be interpreted with this in mind. Last, it is important to take into consideration differences in participants between the normal-weight and overweight/obese samples. Specifically, the overweight sample in general was characterized by a lower mean age, greater proportion of girls, and more overweight parents. As such, these differences may have influenced the significant moderators identified.

Despite these limitations, the use of rigorous random- and mixed-effects meta-analytic techniques to explore a number of moderators that had not yet been examined serves as the current study’s major strength. Publication bias analyses were also conducted to assess the extent to which unpublished studies may have influenced the study’s results. The inclusion of these analytic techniques makes the current study the most informative and rigorous examination of parental underestimates of children’s weight to date.

Conclusions

The current meta-analysis indicates that more than half of parents are unaware of their children’s overweight/obese status. Thus, despite heightening global awareness of the increasing rates of childhood obesity and a greater focus on weight in general, many parents remain unable to recognize when their own children are at risk. Pediatricians are well-positioned to take steps to remedy these misperceptions, encourage healthy eating and physical activity, and increase the chances that parents will take the steps necessary to optimize the health of their children.

Footnotes

Ms Lundahl conceptualized the study, coded the original studies, conducted the meta-analyses, and drafted the initial manuscript; Ms Kidwell coded a portion of the original studies, reviewed and revised the manuscript, and approved the final manuscript as submitted; and Dr Nelson contributed to the conceptualization of the study, critically reviewed and revised the manuscript, and approved the final manuscript as submitted.

FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.

FUNDING: No external funding.

POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.